Bag



Nov. 8, 1966 R. c. MUELLER 3,283,672

BAG

Original Filed June 9, 1961 2 Sheets-Sheet l Nov. 8, 1966 R. c. MUELLERBAG 2 Sheets-Sheet 2 Original Filed June 9, 1961 FIG. 6.

FIG. 5.

United States Patent and this application July 2, 1965, Ser. No. 478,51214 Claims. (Cl. 9335) This application is a division of my c-opendingapplication Serial No. 115,964, filed June 9, 1961, issued as U.S.Patent 3,226,009, December 28, 1965.

This invention relates to'methods of making bags, and more particularlya bag made of heat-scalable plastic, such as polyethylene, with meansfor tearing an opening in the bag.

Among the several objects of the invention may be noted the provision ofa bag made of heat-scalable plastic with means for readily tearing anopening in the bag to empty the bag contents; the provision of a bag ofthe class described wherein said means comprises a tearing member, suchas a strip of plastic, for tearing an opening in the bag, the tearingmember being heat-sealed to the bag throughout a portion of its lengthand free of the bag at another portion of its length to provide aportion for grasping to pull the tearing member to tear an Opening inthe bag; the provision of a draw cord bag of the class described havinga top gusset and a tearing member such as described for tearing anopening in the gusset, after which the bag may be closed by the drawcord; and the provision of methods of economically manufacturing suchbags. Other objects and features will be in part apparent and in partpointed out hereinafter.

The invention accordingly comprises the methods hereinafter described,the scope of the invention being indicated in the following claims.

In the accompanying drawings, in which several of various possibleembodiments of the invention are illustrated,

FIG. 1 is a perspective illustrating generally diagrammatically certaininitial steps of a method of this invention for making bags of thisinvention;

FIG. 2 is a perspective illustrating generally diagrammatically theconcluding steps of the method;

FIG. 3 is a view in elevation of a bag made by the method of FIGS. 1 and2, prior to filling thereof;

FIG. 4 is an enlarged vertical section taken on line 44 of FIG. 3,thicknesses being exaggerated;

FIG. 5 is a vertical section taken on line 55 of FIG. 4, thickness beingexaggerated; and

FIG. 6 is a view in side elevation illustrating generallydiagrammatically a modification in the method of this invention.

Corresponding reference characters indicate corresponding partsthroughout the several views of the drawings.

Referring to FIG. 1 of the drawings, there is indicated at 1 acontinuous web of heat-scalable sheet plastic material, such aspolyethylene. The web 1 is drawn from a supply roll 3, and a bead orstrip 5 of molten plastic, such as polyethylene, is extruded by aconventional extruder E onto web 1 as the web moves toward the right inFIG. 1. This bead 5 is applied generally along the longitudinal centerline of the web. Since extrusion is best accomplished continuously, web1 is continuously withdrawn from roll 3 for continuous application ofbead 5 to the web. Thereafter, the web is intermittently fed forward,one bag width interval at a time. This may be accomplished, inconventional manner, by providing for accumulation of the web as it iscontinuously withdrawn from roll 3 in a slack loop L (see FIG. 1) fromwhich bag width intervals of the web may be withdrawn, one at a time,and into which the web is continuously fed at an appropriate rate fromthe roll 3.

At N is indicated a nozzle which is positioned for delivering a lightstream of cooling air on to the bead 5 before it comes in contact withthe web. Air is intermittently delivered to the nozzle through a line 7under control of a suitable valve (not shown) with the delivery timed tooccur at intervals corresponding to the intermittent feed of the web,resulting in chilling of portions 9 of the bead spaced at bag widthintervals to such an extent as to inhibit heat-sealing of these portionsto the web. Portions 10 of the bead between portions 9 remain hot andconsequently become heat-sealed to the web. Thus, bead 5 is preventedfrom becoming securely bonded to the web at a portion 9 on each bagwidth interval of the web and is securely bonded throughout portion 10on each bag width interval. The purpose of preventing portion 9 of thebead in each bag width interval from adhering to the web 1 will becomeapparent.

The web 1 with the bead 5 thereon is then folded on longitudinal foldlines by conventional folding apparatus (not shown) to form superposedfirst and second walls 11 and 13, respectively, with an intuck 15joining these walls. As illustrated, wall 11 is the upper wall, and wall13 is the lower wall. The fold joining the two halves of the intuck isindicated at 17. This is located on the line of the bead 5, and thefolding is such that the head is located within the intuck (i.e.,between the two halves of the intuck).

Now referring to FIG. 2, the folded web with bead '5 thereon is shown astravelling toward the right through apparatus such as shown in U.S.Patent 2,897,729. As the folded web travels through this apparatus,notches 19 are formed in the intuck edge thereof at bag width intervals,by notching means such as indicated at 20. After the web has beennotched, a first cord 21 is fed in between the first wall 11 and theupper half of intuck 15, and a second cord 23 is fed in between thesecond wall 13 and the lower half of intuck 15. The cords are guidedfrom the supplies 25 and 27 around pulleys 29 and 31 into theirrespective positions. Following the insertion of the cords, the walls 11and 13 are heat-sealed to the respective halves of intuck 15 along lineslocated between the cords and the fold 17 by means of upper and lowersealing bars 33 and 35. It will be understood that a separator(corresponding to plate 221 shown in U.S. Patent 2,897,729) is used toseparate the two halves of intuck 15 to prevent them from becomingheat-sealed together. As a result of this heat-sealing operation, eachof the walls 11 and 13 of the web is provided with a hem 37 along theintuck edge thereof, with a cord contained in each hem. The walls areintegrally joined below the heat seals by a gusset 39 (see FIG. 4)constituted by portions of the two halves of intuck 15 below the heatseals. A pair of rollers 41 and 43 effect gripping of the cords 21 and23 to the web to insure the feeding of the cords with the web.

After the formation of hems 37, portions of the cords 21 and 23 whichare exposed in a notch 19 are drawn out of the notch and securedtogether by stapling the portions of the two cords at two points spacedalong the length of the cords. The secured cords are then severedbetween the two points of securement. The drawing out, severing andstapling together of the cords are accomplished by a severing andstapling unit generally indicated at 45, which is fully described in theabove-mentioned patent.

A pair of feed rolls are shown at 47 and 49. These rolls areintermittently driven and thereby cause the intermittent feed of theweb. At 51 is indicated a clamping means for the cords 21 and 23 locatedbetween unit 45 and the intermittent feed rolls 47 and 49. This clampingmeans prevents forward movement of the cords when vacted upon by theunit 45, and permits the latter to draw out the cords, the excessmaterial for the drawnout cords being drawn from the cord supplies 25and 27.

A pair of feed rolls are shown at 47 and 49. These rolls '47 and 49 isheat-sealed and. segmented on transverse lines 53 spaced at bag widthintervals and intersecting the notches 19 to divide it into individualbags B (a portion of a bag B being shown in FIG. 2). The heat-sealingand segmenting means comprises a knife 55 having electrical resistanceheating means incorporated therein, and a backup roll 57 havingvaheat-resistant resilient surface, as shown in US. Patent 2,897,729. At59 is indicated an air pipe positioned to direct .a stream of air forblowing the cut ends of the cords from between the knife 55 and the roll57, also as shown in said patent.

As a result of the above-described operations, each bag '13 comprisesfront and back walls 11 and 13 joined by [heat-sealed seams 61 at thesides, having a top gusset 39 with a tear strip 5 heat-sealed thereto,and being open at the bottom as indicated at 63. The bag consists of asingle piece of plastic material, the top gusset 39 being constituted byportions of the piece of material integral with the walls 11 and 13. Thetop gusset 39 extends from side-to-side of the bag between the walls 11and 13. As a result of forming the heat-sealed bag side seams 61, themargins of the gusset 39 at each end thereof become heat-sealed togetherand are caught in the side seams 61. The top gusset thereforeconstitutes a top closure panel or top wall for the bag. It consists ofa fold of the plastic material, each half thereof being designated 65.Each half is integrally joined to the respective wall 11 or 13 at a foldline 67 which constitutes the top edge of the bag, and the two halvesare integral-1y oined together by the fold 17 (originally the fold ofintuck 15).

The tear strip 5 extends from side-to-side of the bag on the outside ofthe gusset or top wall 39 and generally along the fold 17. The tearstrip is heat-sealed to the gusset throughout a portion 69 of its length(corresponding to a portion where the original head 5 was heatsealed tothe web) and substantially free of the gusset throughout another portion71 of its length (corresponding to a portion 9 where the original head 5was cooled so as not to become completely heat-sealed to the web). Theends of the strip are caught in the side seams 61. The free portion 71of the strip 5 is adapted to be grasped for pulling the strip to tearopen the gusset. In this respect it will be noted that application ofhot portions 10 of head 5 to the web provides thin or weak regions alongthe sides of the head which give a clean tear when the bead or strip 5is pulled. The end of the free portion 71 caught in side seam 61 willpull out of the side seam when the strip is grasped and pulled foropening the gusset.

Each half 65 of the top gusset 39 is secured to the respective wall 11or 13 along a heat-sealed hem-forming seam 72 extending transverselyacross the bag from one side thereof to the other spaced downward fromthe top edge 67 and the cords 21 and 23, but above the gusset fold line17. The hems contain draw cord means comprising lengths of the textilecords 21 and 23 extending through the hems and out of the hems at bothends, and having their ends which extend out of the hems secured bystaples 73. The top corners of the bag are cut out or notched asindicated at 19. These notches 19 are located about the hem seams 72 andaccommodate tlTe draw cord-ends and staples. As will be understood, thedraws cords are for drawing the top of the bag closed after an openinghas been torn in the gusset by means of'te'ar strip 5,

An alternate method of applying a tear strip to the web 1 is shown inFIG. 6. Instead of providing an extruder as shown in FIG. 1, acontinuous strip 75 of heatsea-lable plastic, such as polyethylene, isintermittently withdrawn from a supply roll 7, passes around a guide 79and is applied generally along the longitudinal center line of the web 1which is being intermittently fed forward one bag width interval at atime as previously described. A heat-sealing bar 81 of a length lessthan the bag width interval is provided forward of the guide 79 andbelow the web 1. Mounted above strip 75 and bar 81 is a platen 83. Thebar 81 is adapted to be raised to cause the web 1 and the strip 75 to beheat-sealed together by heat and pressure. During each dwell in themovement of the web 1 the bar is raised into contact with the web. Thusthe strip 75 is heat-sealed to the web throughout a portion of each bagwidth interval and is free of the web at another portion of the bagwidth interval. Since the bar contacts the web 1 rather than the strip,the web will become somewhat weaker along the heat seal than in otherareas, thus facilitating the tearing of the web material by the tearstrip.

Both the strip 5 and the strip 75 may be made thicker than the web 1 toinsure against failure of the strip when it is pulled to tear open thebag.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As various changes could be made in the above methods without departingfrom the scope of the invention, it is intended that all mattercontained in the above description shall be interpreted as illustrativeand not in a limiting sense.

I claim:

1. The method of making bags comprising forming a continuous web of bagmaterial having two superposed walls joined along one edge of the webwith a continuous length of tear strip material adhered to the web onthe outside thereof and extending longitudinally of the web, segmentingthe 'web with the strip thereon on transverse lines at bag widthintervals, and side-seaming the segments, thereby to provide bags eachof which has a tear strip extending from one side thereof to the otheron the outside of the bag, wherein the tear strip is formed by extrudingmolten plastic as a continuous bead, and wherein portions of said headspaced at intervals along the length of the head are cooled prior toapplication of the head to the web, whereby said cooled portions remainsubstantially free of the web and portions of the head between saidcooled portions adhere to the web.

2. The method of making bags comprising adhering a continuous length oftear strip material to a web of bag material with the tear stripmaterial extending longitudinally of the web, folding the web with thetear strip material'thereon longitudinally to provide superposed firstand second walls with the tear strip on the outside, and segmenting thefolded web with the strip thereon on transverse lines spaced at bagwidth intervals and sideseaming the segments, thereby to provide bagseach of which has a tear strip extending from one side thereof to theother on the outside of the bag.

3. The method as set forth in claim 2, wherein the web and the tearstrip material are made of seat-scalable plastic, and said continuouslength of tear strip material is adhered to the web by heat-sealing.

4. The method of making bags as set forth in claim '2,'wherein the tearstrip is formed by extruding molten plastic as a continuous head.

5. The method of making bags as set forth in claim 2, wherein thecontinuous length of tear strip material is applied to the web in suchmanner as to be adhered to the web throughout a portion of each bagwidth interval of the web and substantially free of the web throughoutanother portion of each bag width interval of the web.

6. The method of making bags as set forth in claim 5, wherein heat andpressure are applied to the web and strip in such manner as to cause thestrip to be adhered to the one portion of the web of each bag widthinterval of the web and substantially free of the Web throughout anotherportion of each bag width interval of the web.

7. The method of making bags comprising adhering a continuous length oftear strip material to a web of bag material extending longitudinally ofthe web, folding the web with the tear strip material thereon onlongitudinal fold lines to provide superposed first and second wallsjoined by an intuck with the tear strip Within the intuck, providingopenings in the folded web along the intuck edge thereof at bag widthintervals, supplying a continuous length of cord between each wall andthe intuck, joining each wall to the respective half of the intuck toform hems containing the cords and a gusset joining the walls,segmenting the cords at the opening and segmenting the web alongtransverse lines spaced at bag width intervals and intersecting theopenings, and securing the cord ends together and side-seaming theresultant segments, thereby to provide bags each of which has a hem atthe top of each wall with a cord therein, a top gusset joining thewalls, and a tear strip on the gusset.

8. The method of making bags as set forth in claim 7, wherein the weband the tear strip material are made of heat-sealable plastic, and saidcontinuous length of tear strip material is adhered to the Web byheat-sealing.

9. The method of making bags as set forth in claim 8, wherein the tearstrip is formed by extruding molten plastic as a continuous bead.

10. The method of making bags as set forth in claim 7, wherein thecontinuous length of tear strip material is applied to the web in suchmanner as to be adhered to the web throughout a portion of each bagwidth interval of the web and substantially free of the web throughoutanother portion of each bag width interval of the web.

11. The method of making bags as set forth in claim 8, wherein thecontinuous length of tear strip material is applied to the web in suchmanner as to be heat-sealed to the web throughout a portion of each bagwidth interval of the web and substantially free of the web throughoutanother portion of each bag width interval of the web,

12. The method of making bags as set forth in claim 11, wherein heat andpressure are applied to the web and strip in such manner as to cause thestrip to be adhered to the one portion of the web of each bag widthinterval of the web and substantially free of the web throughout anotherportion of each bag width interval of the web.

13. The method of making bags as set forth in claim 12 wherein heat andpressure are applied to the Web and strip by a heat-sealing bar having alength less than the bag width interval.

14. The method of making bags comprising adhering a continuous length oftear strip material to a web of bag material with the tear stripmaterial extending longitudinally of the web, folding the web with thetear strip material thereon longitudinally to provide superposed firstand second walls with the tear strip on the outside, and segmenting thefolded web with the strip thereon on transverse lines spaced at bagwidth intervals and sideseaming the segments, thereby to provide bagseach of which has a tear strip extending from one side thereof to theother on the outside of the bag, wherein the continuous length of tearstrip material is applied to the web in such manner as to be adhered tothe web throughout a portion of each bag width interval of the web andsubstantially free of the Web throughout another portion of each bagwidth interval of the web, and wherein the tear strip is formed byextruding molten plastic as a continuous bead, and wherein portions ofsaid bead spaced at intervals along the length of the head are cooledprior to application of the head to the web, whereby said cooledportions remain substantially free of the web and portions of the beadbetween said cooled portions adhere to the Web.

References Cited by the Examiner UNITED STATES PATENTS 2,554,160 5/1951Von Gunten 931 X 2,897,729 8/ 1959 Ashton et al 93-8 2,946,434 7/ 1960Brina 2295 1 2,960,425 11/ 1960 Sherman.

3,034,941 5/1962 Hessenthaler et al. 156-167 X 3,098,601 7/1963 Andersonet al 229-51 3,191,507 6/1965 Cowie 93-1 BERNARD STICKNEY, PrimaryExaminer,

1. THE METHOD OF MAKING BAGS COMPRISING FORMING A CONTINUOUS WEB OF BAGMATERIAL HAVING TWO SUPERPOSED WALLS JOINED ALONG ONE EDGE OF THE WEBWITH A CONTINUOUS LENGTH OF TEAR STRIP MATERIAL ADHERED TO THE WEB ONTHE OUTSIDE THEREOF AND EXTENDING LONGITUDINALLY OF THE WEB, SEGMENTINGTHE WEB WITH THE STRIP THEREON ON TRANSVERSE LINES AT BAG WIDTHINTERVALS, AND SIDE-SEAMING THE SEGMENTS, THEREBY TO PROVIDE BAGS EACHOF WHICH HAS A TEAR STRIP EXTENDING FROM ONE SIDE THEREOF TO THE OTHERON THE OUTSIDE OF THE BAG, WHEREIN THE TEAR STRIP IS FORMED BY EXTRUDINGMOLTEN PLASTIC AS A CONTINUOUS BEAD, AND WHEREIN PORTIONS OF SAID BEADSPACED AT INTERVALS ALONG THE LENGTH OF THE BEAD ARE COOLED PRIOR TOAPPLICATION OF THE BEAD TO THE WEB, WHEREBY SAID COOLED PORTIONS REMAINSUBSTANTIALLY FREE OF THE WEB AND PORTIONS OF THE BEAD BETWEEN SAIDCOOLED PORTIONS ADHERE TO THE WEB.